Early in the game, New Orleans tried to run a screen against Miami. What exactly is a screen? Well, its a passing play to a back or widereceiver a few yards down the field. But, the cool thing is that the offensive linemen don't block the defenders, instead they move out to be blockers for the intended receiver.
The object is to get the defenders rushing upfield at the QB, and then to quickly get a pass off to the back who can use his blockers for a decent gain. Its like a running play from a pass.
Anyway, the Saints were running this formation, and I've approximated the various movements of the players.
At the snap, Brunnell does a play fake (pretends to handoff to the back), and drops back.
The intended reeciver fakes a block and then gets a few yards upfield to make a catch. The defenders are all trying to get to the QB.
But something interesting is happening along the o-line - none of the players are getting out to block for the receiver.
So, finally Brunell gets the pass off, but you can see the RB is on his own, and the LB is in a good spot to make a play, and does.
In general, the best way to defend the screen is to be aware that when as a d-lineman you are not being blocked, there's some trickery going on. And as a LB, if you see it developing that way to be sure you cover your responsibility, such as watching the back.
And if the linemen all move out, you better be ready. I might assume in this case that the Saints were trying a variation where they didn't put a blocker out there to try and confuse the LB (Miles, I think) into not being sure where the play was going.
In any case, it worked out for the Phins as they snuffed out this and many other screens during the game.